From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.1 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C8CFAC2BA83 for ; Wed, 12 Feb 2020 15:21:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8D5ED21734 for ; Wed, 12 Feb 2020 15:21:30 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="T/FBzZ1f" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728539AbgBLPVa (ORCPT ); Wed, 12 Feb 2020 10:21:30 -0500 Received: from bombadil.infradead.org ([198.137.202.133]:48376 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727519AbgBLPV3 (ORCPT ); Wed, 12 Feb 2020 10:21:29 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=kOxp9mEib8PrWpqKIrmfxByXwLZKLOabbiFYit+STus=; b=T/FBzZ1fg4VcMPcvl5h5zyNeuk zlTHtdit3LTaes4nIEkPpGE1fDCfv+JErwZFbOilw5xufCgKrFEurxsKJgwtj82sUZ/j5G9CzJWbU Xn5tdNqwu7aFLopuefh9QNEo+jqql0wGcNLqzklxy1wvzUKq7I30pjfmpeSoBf7z++wbt7j8nMnLv opCT5RVRZ4ne1rCAZVO5upd+FlGmI3lvBJEGNAmSRV3BkLxJGWNTAYFVqaJSw39jq0xRzh6aEl0Ug sOd9WcZKV2O4mChI3z3jt8eDSY4K68bXGdD+v+P5crQsZVSqEYBrmtFdjsWH/fnPXjA6m0ZLE+FpN /5gwcmrA==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by bombadil.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1j1tp0-0004Ge-BL; Wed, 12 Feb 2020 15:21:02 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 7F3DF30220B; Wed, 12 Feb 2020 16:19:11 +0100 (CET) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 8886A2032662E; Wed, 12 Feb 2020 16:21:00 +0100 (CET) Date: Wed, 12 Feb 2020 16:21:00 +0100 From: Peter Zijlstra To: Steven Rostedt Cc: Will Deacon , linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, james.morse@arm.com, catalin.marinas@arm.com, mingo@kernel.org, joel@joelfernandes.org, gregkh@linuxfoundation.org, gustavo@embeddedor.com, tglx@linutronix.de, paulmck@kernel.org, josh@joshtriplett.org, mathieu.desnoyers@efficios.com, jiangshanlai@gmail.com Subject: Re: [PATCH 0/8] tracing vs rcu vs nmi Message-ID: <20200212152100.GV14897@hirez.programming.kicks-ass.net> References: <20200212093210.468391728@infradead.org> <20200212100106.GA14914@hirez.programming.kicks-ass.net> <20200212105646.GA4017@willie-the-truck> <20200212093235.2be06208@gandalf.local.home> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200212093235.2be06208@gandalf.local.home> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Feb 12, 2020 at 09:32:34AM -0500, Steven Rostedt wrote: > I've been trying to get rid of notrace around the kernel, not add more. As is abundantly clear, I hope, we really need more this time. You want to trace RCU itself, the concequence is we _MUST_NOT_ trace the early NMI code until we can distinguish we're *in* NMI code. There really is no 2 way about it; and I'm not going to wait until some poor sucker trips over it.